Lecture: Anomalies of accommodation, convergence & its management

1. Anomalies of accommodation,
convergence & management
Mohammad Arman Bin Aziz
Instructor, Optometry
ICO

2. Asthenopia
• Term for describing a number of symptoms
like:
Eyestrain
Easy fatigability after reading
Heaviness of lids
Sleepiness after reading
Headache

3. Causes of Asthenopia
• Uncorrected refractive errors.
• Defects of ocular motility.
• Accommodation and convergence anomalies

4. Accommodation
The process by which the crystalline lens
changes its power.
Association with
Convergence
Pupillary miosis
Near triad

5. Anomalies of accommodation
• Diminished or deficient accomodation:
– Physiological( presbyopia)
– Pharmacological (cycloplegia)
– Pathological
• Insufficiency of accommodation
• ill-sustained accommodation
• Inertia of accommodation
• Paralysis of accommodation

6. Cont.…
• Increased accommodation:
– Excessive accommodation
– Spasm of accommodation

7. Presbyopia (eyesight of old age)
• Not an error of refraction.
• Condition of physiological insufficiency of
accomodation.
• Progressive fall in near vision.

8. causes
• Age related changes in the lens which
includes:
– Decrease in the elasticity of lens
– Increase in the size and hardness(sclerosis) of lens
substance which is less easily moulded.
• Age related decline in ciliary muscle power

9. Symptoms:
• Difficulty in near vision
• Asthenopic symptoms
• Intermittent diplopia at near because of
interrelationship between accommodation
and convergence.

10. Management
• Optical correction:
– Convex lenses of appropriate power.
• Add:
– difference between the distance correction and the
strength needed for near vision.
• A rough estimate for the presbyopic add for various age
levels is:
– 45 years: +1.00 to +1.25Ds
– 50 years: +1.50 to +1.75Ds
– 55 years: +2.00 to +2.25Ds
– 60 years: +2.50 to +3.00Ds

11. Surgical treatment
• Corneal procedure:
– non ablative corneal procedure
– Laser based corneal procedure
• Lens based procedure
– Refractive lens exchange(RLE)
– Phakic refractive lens
• Sclera based procedure
– Anterior ciliary sclerotomy with tissue barrier
– Scleral spacing procedure.
– Scleral ablation with Erbium(Er.):YAG laser

12. Insufficiency of accommodation
• Accommodative power less than normal
physiological limits for patient ‘s age.
• Should not be confused with presbyopia in
which the physiological insufficiency of
accommodation is normal for age.

13. causes
• Premature sclerosis of lens
• Weakness of ciliary muscle due to systemic causes of
muscle fatigue like:
• Debilitating illness
• Anemia
• Malnutrition
• Diabetes
• Stress
• Weakness of ciliary muscle due to local causes like
irodocyclitis.

14. Clinical features
• Headache, fatigue and irritability of eye.
• Near work is blurred
• Intermittent diplopia
• Asthenopic symptoms >>> blurring of vision

15. • The above symptoms are stable in the
accommodative insufficiency of lenticular
origin.
• When the condition is due to ciliary muscle
weakness, the symptoms may improve:
– with the improvement of exciting factor
– betterment in general health
– Relaxation from work or worry

16. Treatment
• Treatment of the cause.
• Near vision spectacle.
• Accommodation exercise.

17. Ill sustained accommodation
• Condition of accommodation fatigue.
• Although the range of accommodation is
normal, it cannot be sustained for a sufficient
time.
• Causes patient’s NPA to recede during close
work.

18. Clinical features
• Symptoms similar to that of accommodative
insufficiency.
• Pt. complains of tiredness very soon on
intense near work.
• Pt’s NPA gradually recedes and near vision
becomes blurred.

19. Treatment
• Curtailing the near work during:
– Debilitating illness
– General tiredness
– When pt. is relaxed in bed
• Visual hygiene with good illumination and
posture during study.

20. Accommodation inertia
Also known as accommodative infacility.
Condition of difficulty in adjusting the
accommodation according to the distance of
the object of regard so as to gain clear vision.
Cycles per minute by flipper
Usually rare condition.

21. Clinical features
It takes some time and effort to focus a near
object after looking at distant.
Usually does not assume any serious
preposition.
Occasionally may give rise to some trouble
and annoyance.

22. Treatment
• Correcting any associated refractive error.
• Accommodation exercise.

23. Paralysis of accommodation
Also known as cycloplegia.
Complete absence of accommodation.

24. Causes
• Drug induced: due to the effect of atropine,
homatropine or other parasympatholytics.
• Internal ophthalmoplegia(paralysis of ciliary
muscle and sphincter pupillae) associated
with:
• Diphtheria, diabetes, chronic alcoholism, cerebral or
meningeal diseases and mild head injury.
• Paralysis of accommodation as a component
of complete 3rd nerve paralysis..

25. Clinical features
Blurring of near vision (previously
emmetropic and hyperopic eye).
Photophobia (glare).
Examination reveals abnormal receding of
near point and markedly decreased range of
accommodation.

26. Treatment
• Self recovery occurs in drug induced paralysis
and diphtheria cases.
• Dark glasses to reduce glares.
• Convex lens for near vision if paralysis is
permanent.

27. Lag of accommodation
• Accommodative response is
smaller than accommodative
demand.
• Causes asthenopic symptoms.
• Can be found by dynamic
retinoscopy.
• Corrected by giving addition
for near.

28. Excessive accommodation
Pt. exerts more than normal accommodation
for performing certain near work.
It is within voluntary control and is
intermittent process.
Whereas, spasm of accommodation is the
prolong use of excessive accommodation.

29. causes
Young hyperopes frequently use excessive
accommodation as a physiological adaptation.
Young myopes performing excessive near work
may also use excessive accommodation in
association with excessive convergence.
Astigmatic error in young person
Use of improper or ill- fitting spectacle.

30. Precipitating factor
Large amount of near work.
Low or excessive illumination of working
environment.
General debility, physical and mental ill
health.

31. Clinical features
Varying degree of blurred vision
(pseudomyopia}.
Symptoms of accomodative asthenopia.
Both far and near point are brought nearer to
the eye.

32. Treatment
• Optical correction: refractive error corrected
after cycloplegic refraction.
• General treatment:
– Near work should be forbidden for a period.
– Thereafter it should be curtailed.
– General health condition should be maintained.

33. Spasm of accommodation
• Spasm of accommodation refers to exertion
of abnormally excessive accommodation,
which is out of voluntary control of the
individual.

34. Causes
• Drug induced: strong miotics like echothiophate.
• Spontaneous spasm: children with high
refractive error.
• Iridocyclitis: causes ciliary spasm

35. CONT….
• Spasm of near reflex: seen in tensed or
disturbed individuals with excessive
accommodation, convergence and miosis.
• Lesion of the brain: meningitis , encephalitis are
associated with ciliary spasm.
• Toxic reaction of poison: eg sulphonamides,
arsenic, smoking

36. Clinical features
• Blurring of vision due to induced pseudomyopia.
• Headache and browache.
• Near point is abnormally close.

37. Treatment
• Relaxation of ciliary muscle: complete ciliary
paralysis with atropine for 4 weeks or more.
• Optical treatment: proper refractive correction in
the presence of ametropia.
• General treatment:
– near work should be forbidden or curtailed.
– The general condition of the patient should be improved.

38. Convergence
• Disjugate movement
• Both eyes move inward so that the lines of sight
intersect in front of eye.
• Allows bifoveal single vision maintained at any
fixation distance.
• Does not deteriorate with age.
• May deteriorate in certain abnormal conditions.
• Can be improved by exercises.

39. Anomalies of convergence
• Convergence insufficiency:
– Inability to obtain or maintain adequate
binocular convergence.
– Most common cause of ocular asthenopic
symptoms.

40. Etiology
• Primary or idiopathic:
– In many cases, exact etiology is not known.
– May be associate with:
• Wide IPD
• Delayed or inadequate functional development
• General debility
• Psychological instability
• Over work or worry

41. • Refractive :
– Associated with uncorrected high hyperopia and
myopia.
• Diseases of the accommodative convergence
mechanism result in convergence insufficiency
in patients as follows:
– High hyperopes (>5D) usually make no effort to
accommodate and there is deficient accommodative
convergence.
– Myopes may not need accommodation and thus lack
accommodative convergence.

42. • Presbyopia:
• Muscular imbalances
– Exophoria
– IXT
– Vertical muscle imbalances
• Consecutive convergence insufficiency :
– May occur following either recession of medial
recti or resection of lateral rectus muscle.

43. Clinical features:
• Clinical problem in patient who does intense
near work.
– Children with increased school work.
– Desk workers
– Computer users
– Precision workers
• Symptoms can be divide as:
– Symptoms due to muscular fatigue
– Symptoms due to failure to maintain BSV

44. Symptoms due to muscular fatigue
• Due to continuous use of neuromuscular power.
• Eye strain and sensation of tension around globe.
• Headache and eye ache after intense near work and
relieved when eyes are closed.
• Difficulty in changing focus from distance to near
objects.
• Itching, burning and soreness of eyes and even
hyperemia of nasal half of the conjunctiva.

45. Symptoms due to failure to
maintain BSV
• Blurred vision and crowding of words while
reading.
• Intermittent crossed diplopia for near under the
condition of fatigue.
• Characteristically one eye will be closed or closed
while reading to obtain relief from visual fatigue.

46. Treatment
• Excellent prognosis in majority cases.
• Optical:
– proper refractive correction for any presence of
ametropia.
– Myopes given full correction and hyperopes
undercorrected to stimulate accommodation.
– In adults older than 40, proper presbyopic correction
should be given.

47. Orthoptic treatment
• Exercise to improve NPC:
– Advancement exercise(pencil push up exercise)
– Jump convergence exercise
• Exercise to increase amplitude of fusional
convergence:
– Convergence exercise with prisms(BO)
– Convergence exercise using synoptophore
– Exercise using convergence card.
– Physiological diplopia exercise using stereogram in the
uncrossed position.
– Convergence exercise using diploscope.

48. • Training of voluntary convergence.
• Relaxation exercises:
– Physiological diplopia exercise using cat stereograms
in crossed position.
– Divergence exercise on synaptophore
– Divergence exercise on prisms
• Prism therapy:
– Base –in prism reading glasses or bifocals with
prism in the lower segment are useful as relieving
prism.
– Relieving prisms and bifocals should be avoided in
young age.

49. Surgical treatment
• As a last resort, when all other measures fail.
• When it is associated with large exophoria at
near.
• Medial muscle resection can be performed in
one or both eyes.

50. Convergence paralysis:
• Total lack of convergence.
• Etiology:
– Occurs Secondary to some organic diseases of the brain.
– The organic brain lesions are:
• Head injury
• Encephalitis
• Disseminated sclerosis
• Tabes dorsalis
• Narcolepsy
• Tumors

51. Clinical features
• Convergence is completely absent.
• Exotropia and crossed diplopia occurs on
attempted near fixation.
• Accommodation is usually normal. But in
some case it may be reduced or absent.

52. • Parinaud’s syndrome : convergence
paralysis associated with vertical gaze
paralysis.
• Pretectum-posterior commissure syndrome
(dorsal mid brain syndrome):
– Commonly caused by tumor in pineal gland
– Common features are:
• Convergence paralysis
• Vertical gaze paralysis
• Bilateral fourth nerve paralysis
• Lid retraction may occur in some patient.

53. Treatment
• Base in prisms are prescribed at near to alleviate
the diplopia at near.
• Plus lenses with base in prisms in patient with
accommodation insufficiency.
• Occlusion of one eye at near.
• Eye muscle surgery is contraindicate.

54. Convergence spasm
Characterized by intermittent episodes of
maximal convergence usually associated with
spasm of accommodation.

55. • Etiology :
– Functional causes:
• In most of the cases cause is functional.
• In patient with hysteria or neurosis.
– Organic causes:
• Rarely associated with organic lesions like:
– Head trauma
– Encephalitis
– Tabes
– Pituitary adenomas
– Posterior fossa neurofibroma
– Arnold-chiari malformation

56. Clinical features
• Most cases: condition is episodic
• Extreme convergence: eyes in extreme
convergence position resembling abducens palsy.
• Intermittent diplopia
• Blurring of vision.
• Miosis
• Induced myopia
• Psychiatric examination reveal hysteria and
neurosis.

57. Management
• Neurological evaluation: organic lesions are rare
cause of convergence spasm.
• Prolonged atropinization with plus lenses for
near.
• Altered monocular occlusion
• Psychiatric work up and therapy as long term
mearure.

58. References
• Optics and refraction; A.K Khurana
• Clinical refraction; Irvin M Borish, 3rd edition
• Clinical procedures in optometry